Aven (H205) carries the sense of trouble that comes from wickedness — iniquity that produces pain and emptiness. It is used of idolatry (Hosea 4:15; 10:8, where Beth-aven means 'house of wickedness'), of the wicked who plot evil, and of the futility of a life lived apart from God.
Aven is closely tied to vanity and futility. Evil is not merely moral transgression but a hollow, self-defeating endeavor. The prophets connect aven to idol worship — false gods that produce nothing. Psalm 66:18 warns that God will not hear prayer from one who cherishes aven in the heart.